EPA, Montana underestimated mine spill potential

Associated Press

Published
2:08 pm PDT, Wednesday, August 26, 2015

BILLINGS, Mont. — Federal and state regulators underestimated the potential for a toxic blowout from a Colorado mine, despite warnings more than a year earlier that a large-volume spill of wastewater was possible, an internal government investigation released Wednesday found.

The regulators wrongly concluded there was little or no pressure from the millions of gallons of water trapped inside the inactive Gold King mine, the federal Environmental Protection Agency concluded in its probe. It was unclear when that determination was made.

The massive spill occurred Aug. 5 when a government cleanup crew doing excavation work triggered the release of an estimated 3 million gallons of sludge that fouled hundreds of miles of rivers in Colorado, New Mexico and Utah.

The torrent of toxic water released from the mine also shut down some public drinking-water and irrigation systems.

“There was in fact high enough water pressure to cause the blowout,” EPA Deputy Administrator Stan Meiburg said on a conference call after the release of documents summarizing the investigation. He said the error was probably the most significant factor behind the spill.

The EPA previously offered only partial information on events leading up to the spill.

The investigation also revealed that regulators could have drilled into the mine to get a better gauge on how much pressure had built up.

While drilling would have been expensive and technically challenging, “this procedure may have been able to discover the pressurized conditions that turned out to cause the blowout,” the documents say.